Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already establish that this is a non-read-only, non-destructive, non-idempotent, closed-world operation. The description adds meaningful context beyond that: the result is empty, it is created to scale, it lands in the user's account, and the call returns an ID that later calls need. It doesn't state that repeated calls create separate plans, though the workflow sentence partly compensates.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The trigger is front-loaded, the effect and return value come next, and the closing sentence redirects to the correct tools and rules out the wrong behavior. Every clause carries weight, and the object list is short enough to justify itself.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a one-parameter creation tool with no output schema, this covers the trigger, the effect, the return value, and the follow-up path (edit_project, open_editor). An agent has everything it needs to call this correctly and route the next step.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% for the single parameter, and the schema example ("Lake house") already conveys the naming intent. The description adds no further guidance on naming the plan, so it doesn't beat the baseline established by a fully documented schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb and resource ("Starts a new empty plan") and states the return value ("returns its ID"). It also scopes the object types it covers (house, apartment, office, room, floor plan), which separates it from siblings like edit_project and open_editor.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives an explicit trigger ("when someone asks to design, draw or plan..."), an explicit precondition ("no plan of theirs fits"), named follow-on tools (edit_project, open_editor), and explicit exclusions ("do not describe a design in words or generate a picture"). Nothing about when to reach for this tool is left to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.